If we do not support viewing a certain file type in the browser, we should not display the option.
As the below recording shows, when clicking view in browser for the following file types, DOCX, PPTX.or XLSX, then it downloads the files instead.
Note
If this is not a bug, and is expected behavior, feel free to close it or contact me and I will do so.
[This comment has been reassigned to allreplies@alfresco.com as part of the Alfresco cloud migration project. The author of this comment was arjunmony] Hi Ayman,
Browser should have the support to view that file, else it will download.